In retina, like in brain, lactate equilibrates across cell membranes via monocarboxylate transporters and in the extracellular space by diffusion, forming a basis for the action of lactate as a transmitter of metabolic signals. In the present paper, we argue that the lactate receptor GPR81, also known as HCAR1, may contribute importantly to the control of retinal cell functions in health and disease. GPR81, a G-protein coupled receptor, is known to downregulate cAMP both in adipose and nervous tissue. The receptor also acts through other down-stream mechanisms to control functions, such as excitability, metabolism and inflammation. Recent publications predict effects of the lactate receptor on neurodegeneration. Neurodegenerative diseases in retina, where the retinal ganglion cells die, notably glaucoma and diabetic retinopathy, may be linked to disturbed lactate homeostasis. Pilot studies reveal high GPR81 mRNA in retina and indicate GPR81 localization in Müller cells and retinal ganglion cells. Moreover, monocarboxylate transporters are expressed in retinal cells. We envision that lactate receptors and transporters could be useful future targets of novel therapeutic strategies to protect neurons and prevent or counteract glaucoma as well as other retinal diseases.

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Background: Household air pollution associated with biomass (wood, dung, charcoal, and crop residue) burning for cooking is estimated to contribute to approximately 4 million deaths each year worldwide, with the greatest burden seen in low and middle-income countries. We investigated the relationship between solid fuel type and respiratory symptoms in Uganda, where 96% of households use biomass as the primary domestic fuel. Materials and Methods: Cross-sectional study of 15,405 pre-school aged children living in charcoal or wood-burning households in Uganda, using data from the 2016 Demographic and Health Survey. Multivariable logistic regression analysis was used to identify the associations between occurrence of a cough, shortness of breath, fever, acute respiratory infection (ARI) and severe ARI with cooking fuel type (wood, charcoal); with additional sub-analyses by contextual status (urban, rural). Results: After adjustment for household and individual level confounding factors, wood fuel use was associated with increased risk of shortness of breath (AOR: 1.33 [1.10–1.60]), fever (AOR: 1.26 [1.08–1.48]), cough (AOR: 1.15 [1.00–1.33]), ARI (AOR: 1.36 [1.11–1.66] and severe ARI (AOR: 1.41 [1.09–1.85]), compared to charcoal fuel. In urban areas, Shortness of breath (AOR: 1.84 [1.20–2.83]), ARI (AOR: 1.77 [1.10–2.79]) and in rural areas ARI (AOR: 1.23 [1.03–1.47]) and risk of fever (AOR: 1.23 [1.03–1.47]) were associated with wood fuel usage. Conclusions: Risk of respiratory symptoms was higher among children living in wood compared to charcoal fuel-burning households, with policy implications for mitigation of associated harmful health impacts.